Endoscopy in the medical field allows internal features of the body of a patient to be viewed without the use of traditional, fully-invasive surgery. FIGS. 1A and 1B collectively illustrate an endoscopic imaging system such as commonly used in the medical field. FIG. 1A generally illustrates the image generation and display components of the system, while FIG. 1B illustrates the data acquisition components of the system. FIG. 1B shows the data acquisition components, which include an endoscope 2, a camera 3, and a coupler 6 connecting the endoscope 2 to the camera 3. The camera 3 acquires color video image data of internal features of a body through a system of lenses in the endoscope 2. FIG. 1A shows the image generation and display components of the system, which include a camera control unit (CCU) 4, a light source unit 7, a monitor 9, a video recorder 10, and a printer 11, which are stored on a mobile cart 12. Various other system configurations are also possible.
High-intensity light is provided to the endoscope 2 by the light source unit 7 through a flexible light conduit 8, such as fiber optic cable. Operation of the camera system can be controlled from the CCU 4. The camera 3 is coupled to the camera control unit (CCU) 4 by a flexible transmission line 5. The transmission line 5 conveys power to the camera 3, video image data from the camera 3 to the CCU 4, and various control signals bi-directionally between the camera 3 and the CCU 4. Image data received by the CCU 4 from the camera 3 are processed and converted to video images by the CCU 4, which are displayed on the monitor 9, and if desired, recorded by the video recorder 10 and/or used to generate static images that can be printed by printer 11.
Light from the light source unit 7 is generated by a replaceable light bulb (not shown in FIG. 1) inside the light source unit 7. The light bulb has a limited lifetime, i.e., eventually it will fail. It is extremely undesirable for the light bulb to fail during surgery, due to the potential danger to the patient posed by a sudden loss of illumination or a delay in surgery to replace the bulb, the risk of explosion of the bulb, and other potential adverse consequences. Therefore, it is necessary to replace the light bulb before a failure occurs.
After a number of hours of use, which can be predicted with reasonable accuracy, the likelihood of failure of the light bulb increases substantially. This number of hours may be considered to be the light bulb's maximum useful lifetime. The manufacturer of the light bulb or the light source unit typically specifies the useful lifetime and/or a warranty period of the light bulb, in terms of hours of use. The manufacturer may offer an incentive to the user (customer) to replace the light bulb prior to expiration of the warranty period and/or the useful lifetime.
However, it is burdensome for users to keep track of the number of hours the light bulb has been used. The light bulb cannot inherently track the number of hours that it has been used, as it lacks any circuitry to do so. Physical limitations that hinder access to low voltage levels on the light bulb generally prevent the use of any conductively powered circuitry to perform this task.
At least one known design for a light source unit attempts to address this problem. The light source unit keeps track of bulb use on its own, without actually knowing the true cumulative use of the bulb, and provides a bulb hours display on the front panel of the light source unit. In this design, the user has to reset the bulb hours display whenever the bulb is replaced. Also, if the user replaces the bulb with a used bulb, the light source unit has no way of knowing this, and there is no way to cause the light source unit to accurately display the true hours of use of the replacement bulb.